fix: run manifest containers as root and drop privileges in entrypoint

The compose file was forcing the container to run as uid 1001, so the
entrypoint could not create /workspace even with sudo configured.

- Remove Dockerfile USER directive so containers start as root
- Make compile_compose use user: 0:0 when the manifest declares a user
- Make the entrypoint drop to the container user via  after setup,
  preserving environment variables and command arguments
- Update unit tests to assert root startup and privilege drop

Quality gates:
- pytest tests/unit: 210 passed
- ruff: clean on changed files
- mypy: clean on changed files

apps/api/tests/.pi-map.index.md

@@ -2,7 +2,7 @@
 dir: apps/api/tests
 
 ## role
-Provides shared test infrastructure and fixtures for the API test suite
+Provides shared testing infrastructure and fixtures for the FastAPI API application tests.
 ## parent
 index: apps/api/.pi-map.index.md
 map: apps/api/.pi-map.md

apps/api/tests/.pi-map.md

@@ -4,11 +4,11 @@ dir: apps/api/tests
 index: apps/api/tests/.pi-map.index.md
 
 ## role
-Provides shared test infrastructure and fixtures for the API test suite
+Provides shared testing infrastructure and fixtures for the FastAPI API application tests.
 ## files
 - conftest.py | Provides shared pytest fixtures for testing a FastAPI application with async SQLite database, authenticated clients, and test data setup. | exp: func:test_client() → Generator[TestClient, None, None], call:create_async_engine, call:engine.begin, call:conn.run_sync, call:asyncio.run, call:init_db, call:async_sessionmaker, call:patch, call:TestClient, call:app.dependency_overrides.pop, call:engine.dispose, func:init_db(), call:engine.begin, call:conn.run_sync, func:override_get_db_session() → AsyncGenerator[AsyncSession, None], call:async_sessionmaker, func:db_session(test_client) → AsyncGenerator[AsyncSession, None], call:app.dependency_overrides.get, call:override_fn, call:gen.asend, call:gen.aclose, call:create_async_engine, call:engine.begin, call:conn.run_sync, call:async_sessionmaker, call:engine.dispose, func:authenticated_client(test_client) → Generator[TestClient, None, None], call:str, call:uuid.uuid4, call:Settings, call:app.dependency_overrides.get, call:override_fn, call:gen.asend, call:User, call:uuid.UUID, call:session.add, call:session.commit, call:gen.aclose, call:asyncio.run, call:create_test_user, call:create_session_cookie, call:test_client.cookies.set, func:create_test_user(), call:app.dependency_overrides.get, call:override_fn, call:gen.asend, call:User, call:uuid.UUID, call:session.add, call:session.commit, call:gen.aclose, func:test_project_and_repo(authenticated_client) → tuple[str, str], call:uuid.uuid4, call:Settings, call:authenticated_client.cookies.get, call:decode_session_cookie, call:uuid.UUID, call:asyncio.run, call:get_user_id, call:app.dependency_overrides.get, call:override_fn, call:gen.asend, call:Project, call:session.add, call:GitRepository, call:session.commit, call:gen.aclose, call:create_project_and_repo, call:str, raise:RuntimeError, func:get_user_id(), call:Settings, call:authenticated_client.cookies.get, call:decode_session_cookie, call:uuid.UUID, func:create_project_and_repo(), call:app.dependency_overrides.get, call:override_fn, call:gen.asend, call:Project, call:session.add, call:GitRepository, call:session.commit, call:gen.aclose, func:admin_client(test_client) → Generator[TestClient, None, None], call:str, call:uuid.uuid4, call:Settings, call:app.dependency_overrides.get, call:override_fn, call:gen.asend, call:User, call:uuid.UUID, call:session.add, call:session.commit, call:gen.aclose, call:asyncio.run, call:create_admin_user, call:create_session_cookie, call:test_client.cookies.set, func:create_admin_user(), call:app.dependency_overrides.get, call:override_fn, call:gen.asend, call:User, call:uuid.UUID, call:session.add, call:session.commit, call:gen.aclose | dep: asyncio, os, typing, unittest.mock, pytest, pytest_asyncio, fastapi.testclient, sqlalchemy.ext.asyncio, src.config, src.models.base, src.main, src.auth.dependencies, uuid, src.auth.session, src.models.user.user, src.models.project.project, src.models.project.git_repository, fastapi, sqlalchemy, aiosqlite, src.models, src.auth
 ## arch
-Pytest fixture-based testing architecture with async SQLite database setup, authenticated HTTP client factories, and modular test data seeding patterns
+Pytest fixture-based architecture using dependency injection, async SQLite test database with transaction isolation, and authenticated client factories for integration testing.
 ## tags
 call:app.dependency, call:create, overrides.get, call:override, fn, call:gen.asend, call:gen.aclose, user
 ## symbols

apps/api/tests/unit/.pi-map.index.md

@@ -2,7 +2,7 @@
 dir: apps/api/tests/unit
 
 ## role
-Comprehensive unit test suite for the API application covering database migrations, configuration, git operations, Docker services, file handling, monitoring, and notification systems.
+Unit test suite for the API application covering core services, utilities, and infrastructure components.
 ## parent
 index: apps/api/tests/.pi-map.index.md
 map: apps/api/tests/.pi-map.md

apps/api/tests/unit/.pi-map.md

@@ -4,7 +4,7 @@ dir: apps/api/tests/unit
 index: apps/api/tests/unit/.pi-map.index.md
 
 ## role
-Comprehensive unit test suite for the API application covering database migrations, configuration, git operations, Docker services, file handling, monitoring, and notification systems.
+Unit test suite for the API application covering core services, utilities, and infrastructure components.
 ## files
 - __init__.py | Empty file with no functionality
 - test_alembic_migrations.py | Unit tests that verify Alembic database migrations are importable, have correct revision identifiers, and declare expected dependencies without requiring a live database. | exp: func:test_home_directory_migration_imports_and_rewrites() → None, call:Path, call:migration_path.exists, call:importlib.util.spec_from_file_location, call:importlib.util.module_from_spec, call:spec.loader.exec_module, call:callable, func:test_merge_migration_resolves_heads() → None, call:Path, call:migration_path.exists, call:importlib.util.spec_from_file_location, call:importlib.util.module_from_spec, call:spec.loader.exec_module, call:callable | dep: importlib.util, pathlib, pytest, importlib
@@ -21,7 +21,7 @@ Comprehensive unit test suite for the API application covering database migratio
 - test_home_path_expansion.py | Unit tests for home directory path expansion (~ and $HOME) in container paths and manifest home directory resolution. | exp: class:TestExpandContainerPath, method:test_tilde_slash_expands(self) → None, call:expand_container_path, method:test_tilde_alone_expands(self) → None, call:expand_container_path, method:test_dollar_home_slash_expands(self) → None, call:expand_container_path, method:test_dollar_home_alone_expands(self) → None, call:expand_container_path, method:test_absolute_path_unchanged(self) → None, call:expand_container_path, method:test_relative_path_unchanged(self) → None, call:expand_container_path, method:test_tilde_in_middle_unchanged(self) → None, call:expand_container_path, method:test_dollar_home_in_middle_unchanged(self) → None, call:expand_container_path, method:test_root_home(self) → None, call:expand_container_path, class:TestGetManifestHomeDir, method:test_with_user_block(self) → None, call:get_manifest_home_dir, method:test_without_user_block(self) → None, call:get_manifest_home_dir, method:test_with_empty_user_name(self) → None, call:get_manifest_home_dir, method:test_with_none_user_name(self) → None, call:get_manifest_home_dir | dep: pytest, src.services.config.config_profile_resolver, src.services.build.manifest_compiler
 - test_instance_service.py | Unit tests for home directory expansion in docker-compose file modification via instance_service | exp: class:TestModifyComposeFile, method:test_extra_volumes_expand_home_dir(self, tmp_path), call:compose_path.write_text, call:modify_compose_file, call:str, call:compose_path.read_text, method:test_working_directory_expands_home_dir(self, tmp_path), call:compose_path.write_text, call:modify_compose_file, call:str, call:compose_path.read_text | dep: pytest, src.services.tool.instance_service
 - test_lifecycle_hooks.py | Unit tests for lifecycle hook helper functions that derive notification titles and determine whether events should trigger notifications. | exp: class:TestDeriveTitle, method:test_known_event_types(self) → None, call:_derive_title, method:test_unknown_event_type(self) → None, call:_derive_title, class:TestShouldNotify, method:test_error_events_are_notified(self) → None, call:_should_notify, method:test_health_changed_running_is_notified(self) → None, call:_should_notify, method:test_created_started_stopped_restarted_deleted_filtered(self) → None, call:_should_notify, method:test_health_changed_non_running_filtered(self) → None, call:_should_notify | dep: pytest, src.services.instance.lifecycle_hooks
-- test_manifest_compiler.py | Unit tests for a manifest compiler that generates Dockerfiles, docker-compose files, and entrypoint scripts from manifest configurations. | exp: class:TestGetManifestHomeDir, method:test_home_directory_in_manifest_wins(self) → None, call:get_manifest_home_dir, method:test_user_name_derives_home(self) → None, call:get_manifest_home_dir, method:test_root_fallback(self) → None, call:get_manifest_home_dir, method:test_empty_home_directory_falls_back(self) → None, call:get_manifest_home_dir, class:TestCompileDockerfileHomeDirectory, method:test_env_home_and_workdir_use_home_directory(self) → None, call:compile_dockerfile, method:test_workspace_symlink_created(self) → None, call:compile_dockerfile, method:test_runtime_working_dir_overrides_home_workdir(self) → None, call:compile_dockerfile, method:test_working_dir_expands_tilde(self) → None, call:compile_dockerfile, class:TestCompileComposeHomeDirectory, method:test_default_repo_mount_synthesized(self) → None, call:compile_compose, method:test_explicit_repo_mount_preserved(self) → None, call:compile_compose, method:test_workspace_name_substituted_in_mount_target(self) → None, call:compile_compose, method:test_working_dir_expands_home(self) → None, call:compile_compose, class:TestCompileEntrypoint, method:test_entrypoint_creates_home_and_workspace(self) → None, call:compile_entrypoint, method:test_entrypoint_uses_root_then_sudo_for_workspace_symlink(self) → None, call:compile_entrypoint, call:entrypoint.find, method:test_entrypoint_fixes_mount_owners(self) → None, call:compile_entrypoint, func:test_compile_dockerfile_creates_config_dirs_for_user() → None, call:compile_dockerfile, func:test_compile_dockerfile_no_user_does_not_create_home() → None, call:compile_dockerfile, func:test_compile_dockerfile_uses_user_npm_prefix() → None, call:compile_dockerfile | dep: pytest, src.services.build.manifest_compiler
+- test_manifest_compiler.py | Unit tests for a manifest compiler that generates Dockerfiles, docker-compose files, and entrypoint scripts based on manifest configurations. | exp: class:TestGetManifestHomeDir, method:test_home_directory_in_manifest_wins(self) → None, call:get_manifest_home_dir, method:test_user_name_derives_home(self) → None, call:get_manifest_home_dir, method:test_root_fallback(self) → None, call:get_manifest_home_dir, method:test_empty_home_directory_falls_back(self) → None, call:get_manifest_home_dir, class:TestCompileDockerfileHomeDirectory, method:test_env_home_and_workdir_use_home_directory(self) → None, call:compile_dockerfile, method:test_workspace_symlink_created(self) → None, call:compile_dockerfile, method:test_runtime_working_dir_overrides_home_workdir(self) → None, call:compile_dockerfile, method:test_working_dir_expands_tilde(self) → None, call:compile_dockerfile, class:TestCompileComposeHomeDirectory, method:test_default_repo_mount_synthesized(self) → None, call:compile_compose, method:test_explicit_repo_mount_preserved(self) → None, call:compile_compose, method:test_workspace_name_substituted_in_mount_target(self) → None, call:compile_compose, method:test_working_dir_expands_home(self) → None, call:compile_compose, class:TestCompileEntrypoint, method:test_entrypoint_creates_home_and_workspace(self) → None, call:compile_entrypoint, method:test_entrypoint_uses_root_then_sudo_for_workspace_symlink(self) → None, call:compile_entrypoint, call:entrypoint.find, method:test_entrypoint_fixes_mount_owners(self) → None, call:compile_entrypoint, func:test_compile_dockerfile_creates_config_dirs_for_user() → None, call:compile_dockerfile, func:test_compile_dockerfile_no_user_does_not_create_home() → None, call:compile_dockerfile, func:test_compile_dockerfile_uses_user_npm_prefix() → None, call:compile_dockerfile, func:test_compile_dockerfile_starts_as_root_and_drops_privileges() → None, call:compile_dockerfile, call:compile_entrypoint, func:test_compile_compose_runs_as_root() → None, call:compile_compose | dep: pytest, src.services.build.manifest_compiler
 - test_migration_metadata.py | Tests Alembic database migration files for correct table definitions and revision chain metadata | exp: func:test_initial_migration_defines_all_core_tables() → None, call:Path(__file__).resolve, call:spec_from_file_location, call:module_from_spec, call:spec.loader.exec_module, func:test_refresh_tokens_migration_has_expected_revision_chain() → None, call:Path(__file__).resolve, call:spec_from_file_location, call:module_from_spec, call:spec.loader.exec_module | dep: pytest, importlib.util, pathlib, pathlib.Path
 - test_monitoring_models.py | Unit tests verifying creation, persistence, and querying of monitoring models (InstanceEvent and HealthCheck) with database migration compatibility. | exp: func:test_instance_event_creation(db_session) → None, call:User, call:uuid.uuid4, call:db_session.add, call:db_session.commit, call:ToolInstance, call:InstanceEvent, call:db_session.refresh, call:isinstance, func:test_health_check_creation(db_session) → None, call:User, call:uuid.uuid4, call:db_session.add, call:db_session.commit, call:ToolInstance, call:HealthCheck, call:db_session.refresh, call:isinstance, func:test_instance_event_query_by_instance(db_session) → None, call:User, call:uuid.uuid4, call:db_session.add, call:db_session.commit, call:ToolInstance, call:InstanceEvent, call:db_session.execute, call:select(InstanceEvent).where, call:result.scalar_one | dep: uuid, datetime, pytest, sqlalchemy, src.models.system.health_check, src.models.system.instance_event, src.models.tool.tool_instance, src.models.user.user
 - test_notification_service.py | Unit tests for NotificationService covering CRUD operations, filtering, sorting, and ownership isolation. | exp: func:notification_service() → NotificationService, call:NotificationService, func:user_a(db_session: AsyncSession) → User, call:User, call:uuid.uuid4, call:db_session.add, call:db_session.commit, func:user_b(db_session: AsyncSession) → User, call:User, call:uuid.uuid4, call:db_session.add, call:db_session.commit, func:test_create_notification(db_session: AsyncSession, notification_service: NotificationService, user_a: User) → None, call:notification_service.create_notification, call:uuid.uuid4, func:test_list_notifications_orders_by_created_at_desc(db_session: AsyncSession, notification_service: NotificationService, user_a: User) → None, call:notification_service.create_notification, call:datetime.now, call:timedelta, call:db_session.commit, call:db_session.refresh, call:notification_service.list_notifications, func:test_list_notifications_excludes_dismissed(db_session: AsyncSession, notification_service: NotificationService, user_a: User) → None, call:notification_service.create_notification, call:notification_service.dismiss, call:notification_service.list_notifications, func:test_list_notifications_unread_only(db_session: AsyncSession, notification_service: NotificationService, user_a: User) → None, call:notification_service.create_notification, call:notification_service.mark_read, call:notification_service.list_notifications, func:test_get_unread_count(db_session: AsyncSession, notification_service: NotificationService, user_a: User) → None, call:range, call:notification_service.create_notification, call:notification_service.mark_read, call:notification_service.get_unread_count, func:test_mark_read_sets_read_at(db_session: AsyncSession, notification_service: NotificationService, user_a: User) → None, call:notification_service.create_notification, call:notification_service.mark_read, func:test_mark_all_read_affects_all_unread(db_session: AsyncSession, notification_service: NotificationService, user_a: User) → None, call:range, call:notification_service.create_notification, call:notification_service.mark_all_read, call:notification_service.get_unread_count, func:test_dismiss_sets_dismissed_at(db_session: AsyncSession, notification_service: NotificationService, user_a: User) → None, call:notification_service.create_notification, call:notification_service.dismiss, call:db_session.execute, call:select(Notification).where, call:result.scalar_one, func:test_mark_read_wrong_owner_raises(db_session: AsyncSession, notification_service: NotificationService, user_a: User, user_b: User) → None, call:notification_service.create_notification, call:pytest.raises, call:notification_service.mark_read, func:test_dismiss_wrong_owner_raises(db_session: AsyncSession, notification_service: NotificationService, user_a: User, user_b: User) → None, call:notification_service.create_notification, call:pytest.raises, call:notification_service.dismiss, func:test_list_notifications_mute_categories(db_session: AsyncSession, notification_service: NotificationService, user_a: User) → None, call:notification_service.create_notification, call:notification_service.list_notifications, func:test_get_unread_count_excludes_dismissed(db_session: AsyncSession, notification_service: NotificationService, user_a: User) → None, call:notification_service.create_notification, call:notification_service.dismiss, call:notification_service.get_unread_count, func:test_dismiss_all_affects_all_non_dismissed(db_session: AsyncSession, notification_service: NotificationService, user_a: User) → None, call:range, call:notification_service.create_notification, call:notification_service.dismiss_all, call:notification_service.list_notifications, func:test_dismiss_all_affects_only_caller(db_session: AsyncSession, notification_service: NotificationService, user_a: User, user_b: User) → None, call:range, call:notification_service.create_notification, call:notification_service.dismiss_all, call:notification_service.list_notifications, func:test_mark_all_read_affects_only_caller(db_session: AsyncSession, notification_service: NotificationService, user_a: User, user_b: User) → None, call:range, call:notification_service.create_notification, call:notification_service.mark_all_read, call:notification_service.get_unread_count | dep: uuid, datetime, pytest, sqlalchemy, sqlalchemy.ext.asyncio, src.models.system.notification, src.models.user.user, src.services.shared.notification_service, NotificationService, Notification, User, AsyncSession
@@ -30,7 +30,7 @@ Comprehensive unit test suite for the API application covering database migratio
 - test_readiness_probe.py | Unit tests for a Docker container readiness probe service that executes commands via docker exec with retry logic. | exp: class:TestExecuteProbe, class:TestIntegrationScenarios | dep: unittest.mock, src.services.shared.readiness_probe, subprocess
 - test_ssh_keys.py | Unit tests for SSH key preparation functionality including file creation, permissions, ownership, and error handling | exp: class:TestPrepareSshKeyFiles | dep: os, pathlib, unittest.mock, pytest, src.services.shared.ssh_keys
 ## arch
-Standard Python unittest/pytest structure with test files mirroring production modules, heavy use of mocking for external dependencies (Docker, subprocess, database), and isolated tests for individual service classes without integration requirements.
+pytest-based unit testing with heavy use of mocking (subprocess, filesystem, database) to test components in isolation without external dependencies.
 ## tags
 test, url, call:notification, git, home, call:, merge, call:db
 ## symbols

apps/api/tests/unit/test_manifest_compiler.py

@@ -237,6 +237,47 @@ def test_compile_dockerfile_uses_user_npm_prefix() -> None:
     assert "ENV PATH=/home/custom/.npm-global/bin:$PATH" in dockerfile
 
 
+@pytest.mark.unit
+def test_compile_dockerfile_starts_as_root_and_drops_privileges() -> None:
+    """The Dockerfile must not set USER so the entrypoint starts as root.
+
+    The entrypoint itself drops privileges to the container user before
+    exec-ing the real command.
+    """
+    manifest = {
+        "base_image": "ubuntu:24.04",
+        "interface_type": "terminal",
+        "user": {"name": "dev", "uid": 1000, "gid": 1000},
+    }
+    dockerfile = compile_dockerfile(manifest)
+    entrypoint = compile_entrypoint(manifest)
+
+    assert "USER dev" not in dockerfile
+    assert 'exec su -s /bin/bash -c "exec \\"$@\\"" dev -- "$@"' in entrypoint
+
+
+@pytest.mark.unit
+def test_compile_compose_runs_as_root() -> None:
+    """The compose service must start as root so the entrypoint can fix /workspace."""
+    manifest = {
+        "base_image": "ubuntu:24.04",
+        "interface_type": "terminal",
+        "user": {"name": "dev", "uid": 1000, "gid": 1000},
+    }
+    variables = {
+        "IMAGE_TAG": "test:latest",
+        "INSTANCE_NAME": "test-instance",
+        "REPO_PATH": "/host/repos/my-app",
+        "WORKSPACE_NAME": "my-app",
+        "TOOL_PORT": 0,
+        "EXTRA_ENV": {},
+        "EXTRA_VOLUMES": [],
+    }
+    compose = compile_compose(manifest, variables)
+
+    assert "user: 0:0" in compose
+
+
 @pytest.mark.unit
 class TestCompileEntrypoint:
     """Tests for the generated permission-fixing entrypoint."""